The fabrication of semiconductor wafers, which are then used for the fabrication of semiconductor devices, is a well developed area of technology. Many different semiconductor wafer fabrication methods exist, and there are also many known methods of making semiconductor devices from prefabricated wafers. Semiconductor devices are now ubiquitous in modern technological devices and apparatus.
While many wafers and semiconductor devices are built on a silicon substrate, or similar material, certain devices are preferably built on a sapphire substrate, such as vertical gallium-nitride (GaN)-based light emitting diode (LED). In some known processes, the sapphire substrate is removed using a laser lift off (LLO) process, exposing the various n-type layers for subsequent etching and removal such that an n-type electrode may contact the lightly doped n-type GaN layer.
However, the known methods of manufacturing vertical GaN-based LED, and other semiconductor devices, have limitations in that the LLO process can be inadequate, damaging, and inefficient for manufacturing reliable, efficient LED. Also, due to the similar etching selectively of the various GaN layers, it can be difficult to differentiate the interface between the different layers. Accordingly, there is a need for a method of making semiconductor devices that solves the shortcomings of known methods.